Spatial augmented reality (SAR) techniques create augmented reality experiences by changing the look of a physical environment with projected light. Whereas many augmented reality approaches involve rendering graphics over a live video feed on handheld or head worn devices, SAR places graphics directly over the physical object, thus not diverting attention of a user from the real world. “See through” head-worn displays can achieve similar effects; however, conventional head-worn displays support a limited field of view and are somewhat bulky, thereby potentially hindering face-to-face interaction between users.
Under the right circumstances, SAR systems can alter an appearance of a surface of an object to make such surface appear as if it is made of a particular material. For example, a SAR system can cause a carpeted floor to appear to a user as a mossy bog. To achieve this effect, a precise geometric model of the physical environment is required. The geometric model is used to alter projected graphics to account for distortion of the projected image caused by variations in real-world surface geometry. Use of SAR, however, is currently limited due to conventional SAR systems supporting augmenting graphics for a single view, and thus conventional SAR systems support a single user.